Hm... I thought I had mentioned it on ocio-dev during the "Got Lut
Formats?" thread. But it's not exactly your run-of-the-mill LUT format.
We've kind of cracked it, but it's been tricky, and really only works
for us in our specific use case. There are a lot of parameters in the
RMD files, but only some of them get used, depending what colorspace
you're using to decode the R3D files. When you look through the XML,
you see a whole lot of information that looks like it would be useful,
but it turns out that most of it is ignored. Not to mention, the colour
science behind what each parameter does is totally in Red's black box
SDK, and it seems to change slightly with every version of their
software, so keeping up is a little bit difficult.
Our scenario is that we receive DPX files in RedLogFilm colourspace
without any metadata applied. Call these the "raw scans" where the only
thing you need to know when decoding is what ISO and colour temperature
the camera was set to. Typically (and hopefully) these are set and
locked down once for the show, or perhaps there are two or three
variations for different environments (kind of like choosing your film
stock). We work on the log material and then want to apply the RMD at
the end for delivery back to editorial, while keeping the ungraded shots
clean for delivery to the DI (since the RMDs, while useful for dailies,
are basically tossed when the DI session starts so they can grade from
scratch. This isn't always the case, though.)
The problem is that the RMD can only be applied at the time that the R3D
is decoded, using either RedCine-X, Nuke, Hiero, Scratch, etc. Simon's
mention of Redline being able to turn the RMD into a LUT that can be
applied after the decode is interesting though... I haven't heard of
that, and if it works, that would certainly solve this whole issue. RED
themselves have told me that this wasn't possible, though this was like
8 months ago, so much may have changed.
What we ended up doing was taking an R3D, decoding to RedLogFilm, and
then figuring out how to achieve the effects of the RMD parameters using
standard Nuke nodes. This was a bit of a data collection experiment,
wedging out increments of each knob to absurd extents and fitting curves
to figure out exactly what they were doing, and then deciding what node
to use to get the same result in some simple, predictable fashion. Wrap
all that up in a gizmo that looks up the correct LUT for the shot from
Shotgun, parses the XML, and then dumps the parameters back into the
gizmo to apply the various colour corrections. It actually works really
well and saves us a ton of time we'd otherwise have to spend creating
throwaway grades just to be able to submit shots to editorial (though
they will help get your shots approved... )
It's not totally 100% though. I'm pretty sure that when you apply the
corrections in the R3D decoder (either manually, or looked up from an
RMD), they are wrapped up in the full decoding chain that makes it
impossible to really duplicate the result perfectly. As well, as Nuke's
tooltips accurately state, the RED SDK returns 16-bit integer data from
its colour correction operations instead of the nice floating point
workflow that Nuke has.
If you've read this far hoping for some code snippets, I do apologize.
I'd love to share it, but I'm probably not allowed, at least at this
time. I can tell you that it's definitely possible and it's a fun
science project to get it all working. Happy to share tips and answer
questions. Sorry for being a tease :)
-A
On 03/21/2012 12:27 PM, Jeremy Selan wrote:
This is the first I've heard of adding .rmd support to OpenColorIO,
but by all means if you send me some example files (off list) I'll be
happy to look into it.
-- Jeremy
On 03/21/2012 02:46 AM, Simon Björk wrote:
Hi all,
I remember a few weeks back there was a discussion of creating viewer
luts for Red r3d files using the sidecar .rmd files. Apparently luts
can be created using Redline, but I haven't found any documentation
on this. Has anyone successfully created a for example lin2Redgamma
viewing lut? Maybe OpenColorIO could be extended to read rmd files?
Cheers,
Simon
--
--------------------------------
Stiller Studios
Lidingö/Sweden
Simon Björk
Stiller Studios
+46 (0)8 555 23 560
Ekholmsnäsvägen 40, S-181 41 Lidingö
[email protected] <mailto:[email protected]>
www.stillerstudios.se <http://www.stillerstudios.se>
find us:
http://www.eniro.se/query?search_word=stiller+studios&geo_area=liding%F6&what=all
<http://www.eniro.se/query?search_word=stiller+studios&geo_area=liding%F6&what=all>
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